A motor assembly includes a rotation shaft, an impeller installed at one side of the rotation shaft, a rotor mounted at the other side of the rotation shaft to be spaced apart from the impeller along an axial direction of the rotation shaft, a stator surrounding an outer face of the rotor such that the stator is spaced apart from the rotor along a radial direction of the rotation shaft, a first bearing installed at the one side of the rotation shaft between the impeller and the rotor, and a second bearing installed at the other side of the rotation shaft, opposite to the first bearing with respect to the rotor, and disposed to be axially closer to the other end of the rotation shaft than the rotor. An outer diameter of the first bearing is larger than an outer diameter of the second bearing.